A somewhat legendary ero ren'ai game, which codified the Gender Bender subgenre of those works. The main character is Takuya Aihara, a science student with a standard-issue brown-haired and gentle hot childhood friend and a hot mad scientist friend, both of which, as you can guess, want to bone him. As another one of Mad Science Chick's experiments goes awry, you turn into a girl, and suddenly you can't meet a single person without them trying to basically rape you. And because you are a girl, you are now automatically unwilling to resist any sexual advances. Either way, you fight[1] your way through your horny sister, a PE teacher, an art class full of horny kids, a guy who got a crush on you, and a goddamn orgy bus, knowing that if you don't change back soon, the transformation will be permanent!

Sweet deal! But, no, not turning back will also always involve your childhood friend and quite possibly the hot science girl never talking to you again, so that's bad. Because the happy ending of course involves not a life consisting entirely of mindless sex with strangers, but cuddlesex with your true love! Indeed, rarely do you learn lessons so poignant and well-presented as in the wonderful world of Hentailand. As such, all of the X-Change games have Multiple Endings, allowing you to choose between mindless rape, cuddlesex, or some other thing most likely involving rape or cuddlesex.

There's also a sequel, simply titled X-Change 2. Once again, the nerdy male protagonist gets gender bent by an experiment, and suffers similar experiences from the last time (that is to say, lots of rape). And, as if that weren't enough, the story gets closure with X-Change 3, where a student who Takuya once slept with gets him to drink another gender changing formula.

The series doesn't stop there, however. There is also the Yin-Yang! X-Change Alternative series, which centers around other people turning into girls and getting raped (because strike: they were running out of plots for Takuya they wanted to change things). Yin-Yang! X-Change Alternative focuses on Kaoru Sakurazuka, a boy with the attitude of a 25-year old man and the face of a 14-year old girl. As you can guess, Kaoru accidentally drinks a vial of experimental medicine, waking next morning with "girl parts" [2] and an instant harem. Yin-Yang! X-Change Alternative 2 has a similar plot, save for the fact that the protagonist switches bodies with his best friend by Mad Science Chick's new experiment. So when you get raped in this game, your best friend is technically getting raped along with you. Have fun.

Depraved Bisexual - Natsumi. In fact, even getting engaged doesn't not stop her from wanting to sleep with Takuya as a woman. Dr. Matsunaga is said to sleep with Anything That Moves, but considering she only has sex with women in all three games, this is a borderline Informed Attribute in her case. Also, like Natsumi, she finds Takuya unbelievably hot as a woman.

Dojikko - Megumi in the 2nd game. Her clumsiness is the reason she emphatizes and falls in love with the also rather clumsy male Takuya.

Enforced Method Acting - An in-game example. Miyuki in the second game gets so much into her roles that whoever shares the scene with her is forced into this.

Even the Girls Want Her - Takuya gets a chance to score with women who otherwise wouldn't look at him twice as a girl, where he is apparently far more desirable than he ever was as a guy.

Everything Trying To Kill You - The Hentai equivalent. Takuya gets raped at least once a day, by teachers, customers and even random passersby who aren't even important enough to get an in-game sprite.

Extreme Doormat - Takuya pretty much becomes one when he becomes a woman for every sex scene, as he NEVER tries to fight back. (with one exception, see groin attack below) And even when he's a guy, most of the females have no trouble pushing him around.

Fiery Redhead - Natsumi is definitely very aggressive, Kyoka in the second game is more the passiveagressive kind.

Kaoru from Alternative is pretty fiery even as a guy. Girl!Kaoru is more noticable being more or less a typical Tsundere because her mind's still being of an annoyed male.

First Girl Wins - Asuka, at least in the first two games where her ending is canonized by the sequels.

Groin Attack - When Kouji tries to rape Takuya at some point in the third game, the player is given the option to give him a kick to the crotch. The resulting shot of Kouji lying face-down cradling his balls with Takuya looming over him with a pissed-off face was a Crowning Moment Of Awesome, mainly due to the protagonist's tendency to be an Extreme Doormat most of the time. Too bad it came so late in the series.

Hello, Nurse! - Nurse Matsunaga, full board. Benzaie even shouts this during his Lets Play of the game when she makes her debut.

Hermaphrodite - Kaoru, having problem with his sexual genes, making him able to change from boy to girl and vise-versa with a help of hormone boost drink.

H-Game POV Character - Generally a Type III B, with aspects of the Type IV and I, and the canon endings of each game usually bring him into Type I territory.

Idiot Hero - Most people at school aren't very surprised when Takuya changes gender, because he gets himself involved in weird experiments all the time, including one that caused all his hair to fall out for a while. No matter how often she lands in trouble, Takuya can't seem to learn from his mistakes. Asuka even calls him out on this in the third game where she brings up he wouldn't have turned into a girl the third time if he'd be more cautious of his accepting drinks from his Stalker With A Crush.

If It's You It's Okay - Natsumi only wants Takuya sexually as a girl. Kouji is an even odder case, as he wants Takuya as a girl in any case, but if he turns into one, he doesn't care what gender you are anymore, as long as it's Takuya.

Asuka is another strange case. While it's blatantly obvious she's not at all happy with Takuya being turned into a girl, if Takuya has sex with her as one, she doesn't exactly try to fight it all that hard.

Karma Houdini - EVERYONE. Throughout the series, the protagonist gets raped many times and the perpetrators never face any repercussions whatsoever (with only one exception in the third game).

Two exceptions in the third game. The teacher that rapes you when you try to earn money also gets what he deserves.

Only Six Faces - Strangely enough, Takuya's facial structure is pretty much the same, regardless what his gender is, though given his Bishounen look, this is probably justified.

Rape As Comedy - A bit of a borderline case. Outside of the (many) non-consensual sex scenes, the series is fairly light-hearted with an Idiot Hero as a protagonist. Since it's essentially a guy in a girl's body being raped, rape seems to be the game's equivalent of dropping pidgeon poo on the Butt Monkey protagonist's head. Most of the time after being molested, Takuya shrugs and then moves on.

Rape as Drama - By contrast, the actual female characters in the series don't take molestation nearly as lightly and it tends to leave its marks.

Rape Is Love - Played straight if you end up with Kouji in the 2nd or 3rd game.

Rule of Cool - Chisato adds self-destruct mechanisms to every contraption she builds because she thinks they're cool.

Screw Yourself - Played with. One of the characters in the second game look nigh identical to Takuya as a girl, just with different colored hair.

Shout-Out - The 2nd game has multiple references to another Crowd Title named Tokimeki Check-in! including a mention in a mini-quiz, posters of the main girls on the wall in various screens and Maiko's good ending even has Takuya and Maiko staying at Yamano Inn themselves.

Shrinking Violet - Ayano-chan in the third game. Kouji starts out as this, before Takuya playfully takes his virginity which turns him into a...

Tsundere - Asuka in X-Change 2, where she is far less forgiving and dere-dere than she was in X-Change 1, though she seems to mellow out to a middle ground between her X-Change 1 and X-Change 2 portrayal in X-Change 3.

Victorious Childhood Friend - If you do in all three games. Since the 2nd and 3rd game starts with Takuya and Asuka being together, Asuka's pretty much the canon pairing for the protagonist.

What An Idiot - Takuya makes a very boneheaded mistake in the first game (albeit he's forced by the game to do so) that gets him a Stalker With A Crush in the next two. Said mistake is seducing Kouji as a girl in game one, which prompts Kouji to fall for Takuya as a girl. Thus, he does everything in his power to turn Takuya back into one in the next two games. This only brings him trouble for the rest of the series, which he complains about in universe.

You Bastard - One of the bad endings of X-Change 3 happens if you essentially leave another girl to be raped by several guy friends of Natsumi's, and the game is not shy about all but blatantly stating you should have done the H-Game equivalent of a Heroic Sacrifice instead.